Now it works.
[cbs-scheduler.git] / drivers / of / base.c
blob95e9d8c8a2de94384c98e09c81c026dff0dbbaa4
1 /*
2 * Procedures for creating, accessing and interpreting the device tree.
4 * Paul Mackerras August 1996.
5 * Copyright (C) 1996-2005 Paul Mackerras.
7 * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
8 * {engebret|bergner}@us.ibm.com
10 * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
12 * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell.
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version
17 * 2 of the License, or (at your option) any later version.
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/spinlock.h>
23 struct device_node *allnodes;
25 /* use when traversing tree through the allnext, child, sibling,
26 * or parent members of struct device_node.
28 DEFINE_RAW_RWLOCK(devtree_lock);
30 int of_n_addr_cells(struct device_node *np)
32 const int *ip;
34 do {
35 if (np->parent)
36 np = np->parent;
37 ip = of_get_property(np, "#address-cells", NULL);
38 if (ip)
39 return *ip;
40 } while (np->parent);
41 /* No #address-cells property for the root node */
42 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
44 EXPORT_SYMBOL(of_n_addr_cells);
46 int of_n_size_cells(struct device_node *np)
48 const int *ip;
50 do {
51 if (np->parent)
52 np = np->parent;
53 ip = of_get_property(np, "#size-cells", NULL);
54 if (ip)
55 return *ip;
56 } while (np->parent);
57 /* No #size-cells property for the root node */
58 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
60 EXPORT_SYMBOL(of_n_size_cells);
62 struct property *of_find_property(const struct device_node *np,
63 const char *name,
64 int *lenp)
66 struct property *pp;
68 if (!np)
69 return NULL;
71 read_lock(&devtree_lock);
72 for (pp = np->properties; pp != 0; pp = pp->next) {
73 if (of_prop_cmp(pp->name, name) == 0) {
74 if (lenp != 0)
75 *lenp = pp->length;
76 break;
79 read_unlock(&devtree_lock);
81 return pp;
83 EXPORT_SYMBOL(of_find_property);
86 * Find a property with a given name for a given node
87 * and return the value.
89 const void *of_get_property(const struct device_node *np, const char *name,
90 int *lenp)
92 struct property *pp = of_find_property(np, name, lenp);
94 return pp ? pp->value : NULL;
96 EXPORT_SYMBOL(of_get_property);
98 /** Checks if the given "compat" string matches one of the strings in
99 * the device's "compatible" property
101 int of_device_is_compatible(const struct device_node *device,
102 const char *compat)
104 const char* cp;
105 int cplen, l;
107 cp = of_get_property(device, "compatible", &cplen);
108 if (cp == NULL)
109 return 0;
110 while (cplen > 0) {
111 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
112 return 1;
113 l = strlen(cp) + 1;
114 cp += l;
115 cplen -= l;
118 return 0;
120 EXPORT_SYMBOL(of_device_is_compatible);
123 * of_device_is_available - check if a device is available for use
125 * @device: Node to check for availability
127 * Returns 1 if the status property is absent or set to "okay" or "ok",
128 * 0 otherwise
130 int of_device_is_available(const struct device_node *device)
132 const char *status;
133 int statlen;
135 status = of_get_property(device, "status", &statlen);
136 if (status == NULL)
137 return 1;
139 if (statlen > 0) {
140 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
141 return 1;
144 return 0;
146 EXPORT_SYMBOL(of_device_is_available);
149 * of_get_parent - Get a node's parent if any
150 * @node: Node to get parent
152 * Returns a node pointer with refcount incremented, use
153 * of_node_put() on it when done.
155 struct device_node *of_get_parent(const struct device_node *node)
157 struct device_node *np;
159 if (!node)
160 return NULL;
162 read_lock(&devtree_lock);
163 np = of_node_get(node->parent);
164 read_unlock(&devtree_lock);
165 return np;
167 EXPORT_SYMBOL(of_get_parent);
170 * of_get_next_parent - Iterate to a node's parent
171 * @node: Node to get parent of
173 * This is like of_get_parent() except that it drops the
174 * refcount on the passed node, making it suitable for iterating
175 * through a node's parents.
177 * Returns a node pointer with refcount incremented, use
178 * of_node_put() on it when done.
180 struct device_node *of_get_next_parent(struct device_node *node)
182 struct device_node *parent;
184 if (!node)
185 return NULL;
187 read_lock(&devtree_lock);
188 parent = of_node_get(node->parent);
189 of_node_put(node);
190 read_unlock(&devtree_lock);
191 return parent;
195 * of_get_next_child - Iterate a node childs
196 * @node: parent node
197 * @prev: previous child of the parent node, or NULL to get first
199 * Returns a node pointer with refcount incremented, use
200 * of_node_put() on it when done.
202 struct device_node *of_get_next_child(const struct device_node *node,
203 struct device_node *prev)
205 struct device_node *next;
207 read_lock(&devtree_lock);
208 next = prev ? prev->sibling : node->child;
209 for (; next; next = next->sibling)
210 if (of_node_get(next))
211 break;
212 of_node_put(prev);
213 read_unlock(&devtree_lock);
214 return next;
216 EXPORT_SYMBOL(of_get_next_child);
219 * of_find_node_by_path - Find a node matching a full OF path
220 * @path: The full path to match
222 * Returns a node pointer with refcount incremented, use
223 * of_node_put() on it when done.
225 struct device_node *of_find_node_by_path(const char *path)
227 struct device_node *np = allnodes;
229 read_lock(&devtree_lock);
230 for (; np; np = np->allnext) {
231 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
232 && of_node_get(np))
233 break;
235 read_unlock(&devtree_lock);
236 return np;
238 EXPORT_SYMBOL(of_find_node_by_path);
241 * of_find_node_by_name - Find a node by its "name" property
242 * @from: The node to start searching from or NULL, the node
243 * you pass will not be searched, only the next one
244 * will; typically, you pass what the previous call
245 * returned. of_node_put() will be called on it
246 * @name: The name string to match against
248 * Returns a node pointer with refcount incremented, use
249 * of_node_put() on it when done.
251 struct device_node *of_find_node_by_name(struct device_node *from,
252 const char *name)
254 struct device_node *np;
256 read_lock(&devtree_lock);
257 np = from ? from->allnext : allnodes;
258 for (; np; np = np->allnext)
259 if (np->name && (of_node_cmp(np->name, name) == 0)
260 && of_node_get(np))
261 break;
262 of_node_put(from);
263 read_unlock(&devtree_lock);
264 return np;
266 EXPORT_SYMBOL(of_find_node_by_name);
269 * of_find_node_by_type - Find a node by its "device_type" property
270 * @from: The node to start searching from, or NULL to start searching
271 * the entire device tree. The node you pass will not be
272 * searched, only the next one will; typically, you pass
273 * what the previous call returned. of_node_put() will be
274 * called on from for you.
275 * @type: The type string to match against
277 * Returns a node pointer with refcount incremented, use
278 * of_node_put() on it when done.
280 struct device_node *of_find_node_by_type(struct device_node *from,
281 const char *type)
283 struct device_node *np;
285 read_lock(&devtree_lock);
286 np = from ? from->allnext : allnodes;
287 for (; np; np = np->allnext)
288 if (np->type && (of_node_cmp(np->type, type) == 0)
289 && of_node_get(np))
290 break;
291 of_node_put(from);
292 read_unlock(&devtree_lock);
293 return np;
295 EXPORT_SYMBOL(of_find_node_by_type);
298 * of_find_compatible_node - Find a node based on type and one of the
299 * tokens in its "compatible" property
300 * @from: The node to start searching from or NULL, the node
301 * you pass will not be searched, only the next one
302 * will; typically, you pass what the previous call
303 * returned. of_node_put() will be called on it
304 * @type: The type string to match "device_type" or NULL to ignore
305 * @compatible: The string to match to one of the tokens in the device
306 * "compatible" list.
308 * Returns a node pointer with refcount incremented, use
309 * of_node_put() on it when done.
311 struct device_node *of_find_compatible_node(struct device_node *from,
312 const char *type, const char *compatible)
314 struct device_node *np;
316 read_lock(&devtree_lock);
317 np = from ? from->allnext : allnodes;
318 for (; np; np = np->allnext) {
319 if (type
320 && !(np->type && (of_node_cmp(np->type, type) == 0)))
321 continue;
322 if (of_device_is_compatible(np, compatible) && of_node_get(np))
323 break;
325 of_node_put(from);
326 read_unlock(&devtree_lock);
327 return np;
329 EXPORT_SYMBOL(of_find_compatible_node);
332 * of_find_node_with_property - Find a node which has a property with
333 * the given name.
334 * @from: The node to start searching from or NULL, the node
335 * you pass will not be searched, only the next one
336 * will; typically, you pass what the previous call
337 * returned. of_node_put() will be called on it
338 * @prop_name: The name of the property to look for.
340 * Returns a node pointer with refcount incremented, use
341 * of_node_put() on it when done.
343 struct device_node *of_find_node_with_property(struct device_node *from,
344 const char *prop_name)
346 struct device_node *np;
347 struct property *pp;
349 read_lock(&devtree_lock);
350 np = from ? from->allnext : allnodes;
351 for (; np; np = np->allnext) {
352 for (pp = np->properties; pp != 0; pp = pp->next) {
353 if (of_prop_cmp(pp->name, prop_name) == 0) {
354 of_node_get(np);
355 goto out;
359 out:
360 of_node_put(from);
361 read_unlock(&devtree_lock);
362 return np;
364 EXPORT_SYMBOL(of_find_node_with_property);
367 * of_match_node - Tell if an device_node has a matching of_match structure
368 * @matches: array of of device match structures to search in
369 * @node: the of device structure to match against
371 * Low level utility function used by device matching.
373 const struct of_device_id *of_match_node(const struct of_device_id *matches,
374 const struct device_node *node)
376 while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
377 int match = 1;
378 if (matches->name[0])
379 match &= node->name
380 && !strcmp(matches->name, node->name);
381 if (matches->type[0])
382 match &= node->type
383 && !strcmp(matches->type, node->type);
384 if (matches->compatible[0])
385 match &= of_device_is_compatible(node,
386 matches->compatible);
387 if (match)
388 return matches;
389 matches++;
391 return NULL;
393 EXPORT_SYMBOL(of_match_node);
396 * of_find_matching_node - Find a node based on an of_device_id match
397 * table.
398 * @from: The node to start searching from or NULL, the node
399 * you pass will not be searched, only the next one
400 * will; typically, you pass what the previous call
401 * returned. of_node_put() will be called on it
402 * @matches: array of of device match structures to search in
404 * Returns a node pointer with refcount incremented, use
405 * of_node_put() on it when done.
407 struct device_node *of_find_matching_node(struct device_node *from,
408 const struct of_device_id *matches)
410 struct device_node *np;
412 read_lock(&devtree_lock);
413 np = from ? from->allnext : allnodes;
414 for (; np; np = np->allnext) {
415 if (of_match_node(matches, np) && of_node_get(np))
416 break;
418 of_node_put(from);
419 read_unlock(&devtree_lock);
420 return np;
422 EXPORT_SYMBOL(of_find_matching_node);
425 * of_modalias_table: Table of explicit compatible ==> modalias mappings
427 * This table allows particulare compatible property values to be mapped
428 * to modalias strings. This is useful for busses which do not directly
429 * understand the OF device tree but are populated based on data contained
430 * within the device tree. SPI and I2C are the two current users of this
431 * table.
433 * In most cases, devices do not need to be listed in this table because
434 * the modalias value can be derived directly from the compatible table.
435 * However, if for any reason a value cannot be derived, then this table
436 * provides a method to override the implicit derivation.
438 * At the moment, a single table is used for all bus types because it is
439 * assumed that the data size is small and that the compatible values
440 * should already be distinct enough to differentiate between SPI, I2C
441 * and other devices.
443 struct of_modalias_table {
444 char *of_device;
445 char *modalias;
447 static struct of_modalias_table of_modalias_table[] = {
448 { "fsl,mcu-mpc8349emitx", "mcu-mpc8349emitx" },
452 * of_modalias_node - Lookup appropriate modalias for a device node
453 * @node: pointer to a device tree node
454 * @modalias: Pointer to buffer that modalias value will be copied into
455 * @len: Length of modalias value
457 * Based on the value of the compatible property, this routine will determine
458 * an appropriate modalias value for a particular device tree node. Two
459 * separate methods are attempted to derive a modalias value.
461 * First method is to lookup the compatible value in of_modalias_table.
462 * Second is to strip off the manufacturer prefix from the first
463 * compatible entry and use the remainder as modalias
465 * This routine returns 0 on success
467 int of_modalias_node(struct device_node *node, char *modalias, int len)
469 int i, cplen;
470 const char *compatible;
471 const char *p;
473 /* 1. search for exception list entry */
474 for (i = 0; i < ARRAY_SIZE(of_modalias_table); i++) {
475 compatible = of_modalias_table[i].of_device;
476 if (!of_device_is_compatible(node, compatible))
477 continue;
478 strlcpy(modalias, of_modalias_table[i].modalias, len);
479 return 0;
482 compatible = of_get_property(node, "compatible", &cplen);
483 if (!compatible)
484 return -ENODEV;
486 /* 2. take first compatible entry and strip manufacturer */
487 p = strchr(compatible, ',');
488 if (!p)
489 return -ENODEV;
490 p++;
491 strlcpy(modalias, p, len);
492 return 0;
494 EXPORT_SYMBOL_GPL(of_modalias_node);
497 * of_parse_phandles_with_args - Find a node pointed by phandle in a list
498 * @np: pointer to a device tree node containing a list
499 * @list_name: property name that contains a list
500 * @cells_name: property name that specifies phandles' arguments count
501 * @index: index of a phandle to parse out
502 * @out_node: optional pointer to device_node struct pointer (will be filled)
503 * @out_args: optional pointer to arguments pointer (will be filled)
505 * This function is useful to parse lists of phandles and their arguments.
506 * Returns 0 on success and fills out_node and out_args, on error returns
507 * appropriate errno value.
509 * Example:
511 * phandle1: node1 {
512 * #list-cells = <2>;
515 * phandle2: node2 {
516 * #list-cells = <1>;
519 * node3 {
520 * list = <&phandle1 1 2 &phandle2 3>;
523 * To get a device_node of the `node2' node you may call this:
524 * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args);
526 int of_parse_phandles_with_args(struct device_node *np, const char *list_name,
527 const char *cells_name, int index,
528 struct device_node **out_node,
529 const void **out_args)
531 int ret = -EINVAL;
532 const u32 *list;
533 const u32 *list_end;
534 int size;
535 int cur_index = 0;
536 struct device_node *node = NULL;
537 const void *args = NULL;
539 list = of_get_property(np, list_name, &size);
540 if (!list) {
541 ret = -ENOENT;
542 goto err0;
544 list_end = list + size / sizeof(*list);
546 while (list < list_end) {
547 const u32 *cells;
548 const phandle *phandle;
550 phandle = list++;
551 args = list;
553 /* one cell hole in the list = <>; */
554 if (!*phandle)
555 goto next;
557 node = of_find_node_by_phandle(*phandle);
558 if (!node) {
559 pr_debug("%s: could not find phandle\n",
560 np->full_name);
561 goto err0;
564 cells = of_get_property(node, cells_name, &size);
565 if (!cells || size != sizeof(*cells)) {
566 pr_debug("%s: could not get %s for %s\n",
567 np->full_name, cells_name, node->full_name);
568 goto err1;
571 list += *cells;
572 if (list > list_end) {
573 pr_debug("%s: insufficient arguments length\n",
574 np->full_name);
575 goto err1;
577 next:
578 if (cur_index == index)
579 break;
581 of_node_put(node);
582 node = NULL;
583 args = NULL;
584 cur_index++;
587 if (!node) {
589 * args w/o node indicates that the loop above has stopped at
590 * the 'hole' cell. Report this differently.
592 if (args)
593 ret = -EEXIST;
594 else
595 ret = -ENOENT;
596 goto err0;
599 if (out_node)
600 *out_node = node;
601 if (out_args)
602 *out_args = args;
604 return 0;
605 err1:
606 of_node_put(node);
607 err0:
608 pr_debug("%s failed with status %d\n", __func__, ret);
609 return ret;
611 EXPORT_SYMBOL(of_parse_phandles_with_args);